This Assignee's Harriett U.S. Pat. Nos. 4,668,724; 4,534,926; 4,656,062; 4,810,573; 4,733,989; and 4,787,780; as well as Hayakawa Rubber Company's U.S. Pat. No. 4,366,284 all hereby incorporated by reference, disclose water-swellable clay-containing compositions that are well known water-stop compositions, sold for years in the form of a rope or rod, that are capable of swelling upon contact with water for water-stop purposes.
These prior art compositions contain a water-swellable smectite clay, such as sodium montmorillonite or sodium bentonite, in an amount of about 10% to 90% by weight; polypropene, polybutene, or a mixture in an amount of about 8–65% by weight; and an elastomer, such as butyl rubber, or a plasticizer in an amount of about 1–20% by weight.
The rod-, or rope-shaped water-swellable clay compositions described herein generally are disposed in a joint gap between two adjacent structural numbers, such as between two separately poured concrete sections, during construction. The clay composition, for example, is disposed in contact with a cured concrete section prior to pouring an adjacent concrete section such that the composition is disposed between and in contact with the two concrete sections. By this placement, the rod- or rope shaped clay composition, when swelled by water, expands to profile the adjacent surfaces of the structural members to fill any voids in the joint between the two structural members. The clay compositions, due to the substantial expansion, prevents water penetration in the joint between the adjacent structural members.